In color photographic light-sensitive materials, it has hitherto been known to utilize an interlayer effect as a means for improving color reproducibility. Taking color negative light-sensitive materials for instance, a development inhibitory effect is produced from a green-sensitive layer towards a red-sensitive layer to thereby retard color formation of the red-sensitive layer under white light exposure as compored with color formation under exposure to red light. Since a color negative paper system has a balanced gradation so that an area exposed to white light may be reproduced in gray on a color print, the aforesaid interlayer effect provides a higher cyan density on the negative when exposed to red light than in the case of exposure to gray light. As a result, it is possible to reproduce a red color of higher saturation on the print with cyan development being inhibited. Likewise, the development inhibitory effect from a red-sensitive layer towards a green-sensitive layer results in reproduction of a green color having high saturation.
In order to enhance the interlayer effect, it is known to use an iodine ion which is released from a silver halide emulsion upon development. This technique is to increase a silver iodide content in a layer which produces an interlayer effect and to decrease a silver iodide content in a layer which accepts the interlayer effect. Another process for ensuring the interlayer effect, as disclosed in Japanese Patent Application (OPI) No. 2537/1975, comprises adding a coupler capable of releasing a development inhibitor upon reacting with an oxidation product of a developing agent in a p-phenylenediamine type color developer to a layer that produces an interlayer effect. A still another process for increasing the interlayer effect is called automatic masking, in which a colored coupler is added to cancel unnecessary absorption of a dye image obtaned from colorless couplers. According to this process using colored couplers, an increased amount of the colored coupler can not only mask unnecessary absorption of a colorless coupler but also produce an effect similar to an interlayer effect.
In an attempt to increase saturation of red and to increase image sharpness of a green-sensitive layer to which human eyes are highly sensitive and which is, therefore, visually the most important, the present inventors have found that addition of a DIR compound capable of releasing a highly diffusible development inhibitor to a green-sensitive layer can accomplish the above-described purposes but gives rise to a problem on reproducibility of green. In other words, various green colors that are perceivable by eyes, such as yellowish green, orange-tinged green, cyan-tinged green, brownish green, etc., become indistinguishable. The inventors have conducted extensive studies on this problem and reached the following conclusion.
That is, when an interlayer effect from a green-sensitive layer increases, spectral sensitivity of a blue-sensitive layer in a longer wavelength side and spectral sensitivity of a red-sensitive layer in a shorter wavelength side are reduced due to the interlayer effect so that the sensitivities of the blue-sensitive layer and red-sensitive layer in the spectral region of the green-sensitive layer substantially disappear, and only the green-sensitive layer develops a color to all wavelengths within green light. Development should normally take place in both the green-sensitive layer and other layers, i.e., a red-sensitive layer. However, too great an interlayer effect from the green-sensitive layer inhibits development of the red-sensitive layer, thus resulting in color development in only the green-sensitive layer. As a result, green colors being different in hue tend to be developed in the same color tone making distinction among them difficult.